A drive connection between an engine and torque converter incorporates a flex plate to accommodate misalignment between the centerlines of the engine and the transmission as well as movement due to hydraulic forces in the torque converter. The flex plate is typically connected by threaded fasteners to both the engine crankshaft and lugs welded to the torque converter input shell. It is customary alternative to employ threaded fasteners connected to both the engine flywheel and a flange on the torque converter. In either event, the flex plate is bolted to one member prior to joining the engine and transmission. To assemble the units, they are aligned and a nose on the torque converter is slid into a bushing, or pilot, in the crankshaft. The other connection is then made by inserting a bolt through an access aperture and threading it to an opening in the proper unit. The engine and transmission must then be rotated on their respective axes until another threaded opening is presented to the access aperture so another bolt may be threaded in position. This process is continued until twelve or more bolts are installed and properly tightened. This is a time consuming process. Moreover, the process is subject to errors in that a bolt can be omitted, not completely tightened or cross threaded. In fact, this assembly process may require the need for two employees on a paced assembly line. The disadvantages are compounded every time it is necessary to disassemble the connection for repairs or inspections.
An alternative is to provide a slide-together assembly in the form of a spline or toothed connection. With slide-together interfaces, the engine flywheel and a flange on the torque converter are mated at assembly. The drive interface is maintained by the securement between the housings. However, due to the amount of movement caused by misalignment and/or hydraulic forces in the torque converter, a dry spline or toothed connection does not meet the durability requirements for commercial, on-highway vehicles. Thus, this type connection tends to require lubrication. As a result, these drive interfaces have been limited to off-highway and track-laying types of vehicles where continual maintenance is employed.